Question

find 31st term of AP whose 11th term is 38 and 10th term is 73

Answer 1

A11=A+10d=38. ...1

A10=A+9d=73. ...2
from 1&2
d=-35
a=388
an=a+(n-1) d
an=388+(-1050)
an=-662

Answer 2

Answer: -662

Step-by-step explanation:

We know that d= diff. of two consecutive terms.

=> d= T11-T10

=>d= 38-73

=>d= -35

T11=a+(n-1)d

=>a+10(-35)=38

=>a-350=38

=>a=388

T31=a+(n-1)d

=>T31= 388+30(-35)

=388-1050

=-662